Solar-radiation-shielding material for vehicle window and window for vehicle

ABSTRACT

A solar-radiation-shielding material for vehicle windows reduces the visible light transmittance, and reduces the value of solar radiation transmittance/visible light transmittance. The visible light transmittance of the solar-radiation-shielding material is in the range of 5%. The transmission color of the solar-radiation-shielding material satisfies the Expression 2: −14&lt;a*&lt;2, and −8&lt;&lt;2.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a solar-radiation-shielding materialfor vehicle windows used for a sunroof, a panorama roof, a back window,a rear side window, or a front window of an automobile, an electrictrain, heavy equipment, and so on.

2. Description of the Related Art

Conventionally, as safety glass for, for example, an automobile,laminated glass constituted of two glass plates and asolar-radiation-shielding film disposed between the plates has beenproposed for reducing air-conditioning cooling load and reducing humanfeeling of heat by shielding incident solar energy by the laminatedglass.

For example, Japanese Patent Laid-Open No. S61-277437, Japanese PatentLaid-Open No. H10-146919 and Japanese Patent Laid-Open No. 2001-179887propose heat-ray-shielding plates in which a heat-ray reflective filmcomposed of a transparent resin film deposited with a metal or a metaloxide is bonded to a transparent molded product such as glass, anacrylic plate, or a polycarbonate plate.

However, the heat-ray reflective film is very expensive itself and isalso high cost because complicated processes such as a bonding processare necessary. In addition, since the adhesive properties between thetransparent molded product and the reflective film are not good, theheat-ray-shielding plates have a problem that detachment of the film iscaused by a change with the passage of time.

Furthermore, there are proposed a large number of heat-ray-shieldingplates each composed of a transparent molded product having a surfacedirectly deposited with a metal or a metal oxide, but the production ofsuch heat-ray-shielding plates needs an apparatus that can highlyprecisely control the atmosphere in high vacuum and therefore hasproblems of being low in mass productivity and of being low inversatility.

Furthermore, for example, Japanese Patent Laid-Open No. H6-256541 andJapanese Patent Laid Open No. H6-264050 propose heat-ray-shieldingplates and films produced by kneading an organic near-infrared absorberrepresented by a phthalocyanine-based compound or an anthraquinone-basedcompound with a thermoplastic transparent resin such as polyethyleneterephthalate resin, a polycarbonate resin, an acrylic resin, apolyethylene resin, or a polystyrene resin.

However, in order to sufficiently shield heat rays, a large amount ofthe near-infrared absorber must be blended, and the near-infraredabsorber blended in a large amount causes a problem of decreasingvisible light-transmitting ability. In addition, since an organiccompound is used, the weather resistance is low, and, therefore, theapplication to, for example, window materials of buildings andautomobiles, which are always exposed to direct sunlight, is notnecessarily appropriate.

In addition, Japanese Patent Laid-Open No. H8-217500 discloses laminatedglass constituted of a pair of glass plates and a soft resin layerinterposed between the plates. The soft resin layer containsheat-ray-shielding metal oxide fine particles that are made of tin oxideor indium oxide and have a particle size of 0.1 μm or less.

Furthermore, Japanese Patent Laid-Open No. H8-259279 discloses laminatedglass constituted by disposing an intermediate layer between at leasttwo glass plates. The intermediate layer contains a metal of Sn, Ti, Si,Zn, Zr, Fe, Al, Cr, Co, Ce, In, Ni, Ag, Cu, Pt, Mn, Ta, W, V, or Mo, anoxide, nitride, or sulfide of such a metal, Sb- or F-doped compoundthereof, or a composite thereof, which is dispersed therein.

Furthermore, Japanese Patent Laid-Open No. H4-160041 discloses windowglass for automobiles. The window glass includes transparent plate-likemembers and fine particles made of TiO₂, ZrO₂, SnO₂, and In₂O₃ and aglass component composed of organic silicon or an organic siliconcompound interposed between the members.

Furthermore, Japanese Patent Laid-Open No. H10-29745 discloses laminatedglass having at least an intermediate layer composed of three layersbetween two transparent glass plates. The second layer, i.e., the middlelayer, of the intermediate layer contains a metal of Sn, Ti, Si, Zn, Zr,Fe, Al, Cr, Co, In, Ni, Ag, Cu, Pt, Mn, Ta, W, V, or Mo, an oxide,nitride, or sulfide of such a metal, Sb- or F-doped compound thereof, ora composite thereof, which dispersed therein. The first layer and thethird layer of the intermediate layer are resin layers.

Furthermore, the present applicant proposes in Japanese Patent Laid-OpenNo. 2001-89202 solar-radiation-shielding laminated glass composed of anintermediate layer having a solar-radiation-shielding functioninterposed between two glass plates, wherein the intermediate layer isconstituted of an intermediate film containing hexaboride fine particlesalone; or hexaboride fine particles, ITO fine particles and/or ATO fineparticles, and a vinyl-based resin, or wherein the intermediate layer isconstituted of a solar-radiation-shielding film disposed on the innersurface of at least one of the two glass plates and containing theabove-mentioned fine particles, and an intermediate film interposedbetween the two glass plates and containing the vinyl-based resin.

In addition, Japanese Patent Laid-Open No. 2001-89202 discloses that theoptical characteristics of the solar-radiation-shielding laminated glassto which the hexaboride fine particles alone or the hexaboride fineparticles and the ITO fine particles and/or the ATO fine particles areapplied have a maximum transmittance in a visible light region and showstrong absorption in a near-infrared region to have a minimumtransmittance therein, and thereby the solar-radiation-shieldinglaminated glass is improved in solar radiation transmittance to theorder of 50%, when the visible light transmittance is 70% or more,compared to conventional laminated glass described in Japanese PatentLaid-Open No. S61-277437, Japanese Laid-Open No. H10-146919, JapaneseLaid-Open No. 2001-179887 and Japanese Laid-Open No. H6-256541.

A window having such solar-radiation-shielding properties, tries toincrease both brightness and solar-radiation-shielding properties ashigh as possible. However, in a sunroof, a panorama roof, a back window,a rear side window, and a front window of an automobile, a sunroof ofheavy equipment, and so on, a design that gives priority to howeconomically it shields heat of solar rays, rather than the brightnessis required.

In order to obtain laminated glass that can be practically applied tosuch a vehicle window portion, it is proposed to decrease visible lighttransmittance to control the color tone to cyaneous, gray, bronze(reddish brown), or dark green. However, when the above-describedconditions are satisfied, the value of solar radiationtransmittance/visible light transmittance, which is an index tosolar-radiation-shielding properties, cannot be reduced to be lower thanone, and the laminated glass is thus inferior insolar-radiation-shielding properties and thereby still remains room forimprovement.

The present invention has been accomplished in light of theabove-described problems, and it is an object of the invention toprovide a solar-radiation-shielding material for vehicle windows and awindow for a vehicle, in which the visible light transmittance has beenreduced, the color tone has been controlled to cyaneous, gray, bronze(reddish brown), or dark green, which are highly required, and also thevalue of solar radiation transmittance/visible light transmittance,which is an index to solar-radiation-shielding properties, has beenreduced to less than 1, and the manufacturing cost is low.

SUMMARY OF THE INVENTION

That is, a first aspect of the present invention is asolar-radiation-shielding material for vehicle windows that containsfine particles having a heat-ray-shielding function used in a window ofa vehicle. The fine particles having the heat-ray-shielding function area mixture including at least one type of fine particles selected fromthe group consisting of lanthanum hexaboride, titanium nitride, andtungsten oxide and at least one type of fine particles selected from thegroup consisting of antimony-doped tin oxide, tin-doped indium oxide,and a composite tungsten oxide defined by a general formula: M_(Y)WO_(Z)(0.001≦Y≦1.0, and 2.2≦Z≦3.0). The visible light transmittance of thesolar-radiation-shielding material is in the range of 5% or more and 40%or less. The solar radiation transmittance and the visible lighttransmittance of the solar-radiation-shielding material satisfy thefollowing Expression 1, and the transmission color of thesolar-radiation-shielding material satisfies the following Expression 2:

solar radiation transmittance/visible light transmittance<1,and  Expression 1

−14<a*<2, and −8<b*<2.  Expression 2

A second aspect of the present invention is a solar-radiation-shieldingmaterial for vehicle windows that contains fine particles having aheat-ray-shielding function used in a window of a vehicle. The fineparticles having the heat-ray-shielding function are a mixture includingat least one type of fine particles selected from the group consistingof lanthanum hexaboride, titanium nitride, and tungsten oxide, at leastone type of fine particles selected from the group consisting ofantimony-doped tin oxide, tin-doped indium oxide, and a compositetungsten oxide defined by a general formula: M_(Y)WO_(Z) (0.001≦Y≦1.0,and 2.2≦Z≦3.0), and iron oxide fine particles. The visible lighttransmittance of the solar-radiation-shielding material is in the rangeof 5% or more and 40% or less. The solar radiation transmittance and thevisible light transmittance of the solar-radiation-shielding materialsatisfy the following Expression 3, and the transmission color of thesolar-radiation-shielding material satisfies the following Expression 4:

solar radiation transmittance/visible light transmittance<1,and  Expression 3

−2<a*<14, and 2<b*<12.  Expression 4

A third aspect of the present invention is a solar-radiation-shieldingmaterial for vehicle windows according to the first or second aspect ofthe invention, wherein the tungsten oxide is WO₂ or W₁₈O₄₉.

A fourth aspect of the present invention is a solar-radiation-shieldingmaterial for vehicle windows according to the first or second aspect ofthe invention, wherein the element M contained in the composite tungstenoxide fine particle is at least one selected from the group consistingof Cs, Rb, K, T1, In, Ba, Li, Ca, Sr, Fe, and Sn.

A fifth aspect of the present invention is a solar-radiation-shieldingmaterial for vehicle windows according to the first to fourth aspects ofthe invention, wherein the fine particles having the heat-ray-shieldingfunction have a diameter of 300 nm or less.

A sixth aspect of the present invention is a solar-radiation-shieldingmaterial for vehicle windows according to the first to fifth aspects ofthe invention, wherein the fine particles having the heat-ray-shieldingfunction are surface-treated with at least one type of compound selectedfrom the group consisting of a silane compound, a titanium compound, anda zirconia compound.

A seventh aspect of the present invention is a solar-radiation-shieldingmaterial for vehicle windows according to the first to sixth aspects ofthe invention, and the solar-radiation-shielding material furthercontains at least one type of fine particles selected from the groupconsisting of zinc oxide fine particles, cerium oxide fine particles,and titanium oxide fine particles.

An eighth aspect of the present invention is a solar-radiation-shieldingmaterial for vehicle windows according to the first to seventh aspectsof the invention, wherein the fine particles having theheat-ray-shielding function are contained in a polycarbonate resinmolded product.

A ninth aspect of the present invention is a solar-radiation-shieldingmaterial for vehicle windows according to the eighth aspect of theinvention, wherein the polycarbonate resin molded product is providedwith an abrasion-resistant hard coat layer on at least one surface.

A tenth aspect of the present invention is a solar-radiation-shieldingmaterial for vehicle windows prepared by laminating thesolar-radiation-shielding material according to the eighth or ninthaspect of the invention to another resin molded product.

An eleventh aspect of the present invention is asolar-radiation-shielding material for vehicle windows according to thefirst to seventh aspects of the invention, wherein the fine particleshaving the heat-ray-shielding function are contained in one type ofresin selected from the group consisting of a polyvinyl butyral resin, apolyvinyl acetate resin, and a polyvinyl alcohol resin.

A twelfth aspect of the present invention is a solar-radiation-shieldingmaterial for vehicle windows having a laminated structure including thesolar-radiation-shielding material according to the eleventh aspect ofthe invention interposed as an intermediate film between two laminatedplates, wherein the laminated plates are at least one selected from thegroup consisting of an inorganic glass plate, a polycarbonate resinmolded product, and a polyethylene terephthalate resin molded product.

A thirteenth aspect of the present invention is asolar-radiation-shielding material for vehicle windows according to thetwelfth aspect of the invention, wherein at least one of the laminatedplates is the solar-radiation-shielding material according to the eighthto tenth aspects of the invention.

A fourteenth aspect of the present invention is thesolar-radiation-shielding material for vehicle windows according to thefirst to thirteenth aspects, wherein the solar-radiation-shieldingmaterial for vehicle windows has a shape with a thickness of 2.5 to 30mm and a maximum projected area of 400 to 60000 cm².

A fifteenth aspect of the present invention is a window for a vehicle inwhich a solar-radiation-shielding material for vehicle windows accordingto the first to fourteenth aspects of the invention is used.

ADVANTAGEOUS EFFECTS OF INVENTION

In the solar-radiation-shielding material for vehicle windows and thewindow for a vehicle according to the present invention, it is possibleto provide a solar-radiation-shielding material for vehicle windows anda window for a vehicle that have not been conventionally obtained, inwhich the visible light transmittance has been reduced, the color tonehas been controlled to cyaneous, gray, bronze (reddish brown), or darkgreen, which are highly required, the value of solar radiationtransmittance/visible light transmittance, which is an index tosolar-radiation shielding properties, has been reduced to less than one,and the manufacturing cost is low, and such solar-radiation-shieldingmaterial and the vehicle window can be applied to a sunroof, a panoramaroof, a back window, a rear side window, or a front window of anautomobile, a sunroof of heavy equipment, and so on and can be used forvarious purposes and are therefore industrially useful.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described in detail below.

1. Fine Particles Having a Heat-Ray-Shielding Function

1) Fine particles of at least one type selected from the groupconsisting of lanthanum hexaboride, titanium nitride, and tungstenoxide.

Compounds in the group consisting of lanthanum hexaboride, titaniumnitride, and tungsten oxide have optical characteristics showingabsorption from visible light to near-infrared light, in particular,selectively absorbing near-infrared light of 780 to 1200 nm.Furthermore, the group has very strong abilities of absorbing visiblelight and near-infrared light with respect to an addition amount perunit area and can effectively impart a heat-ray-shielding function to abase material in a small addition amount. However, the compounds in thegroup are low in the ability of absorbing infrared light of 1200 nm ormore and therefore have a problem that they cannot shield energy in along-wavelength region contained in sunlight.

a) Lanthanum Hexaboride

It is preferable that the surface of lanthanum hexaboride used in thepresent invention be not oxidized, but usually the surface is slightlyoxidized in many cases, and it is inevitable that the surface isoxidized to some extent in a process of dispersing the fine particles.However, even in such a case, the heat-ray-shielding effect is stilleffectively expressed.

In addition, the lanthanum hexaboride fine particles can obtain a higherheat-ray-shielding effect with the increasing degree of crystallinity,but even if the fine particles have low crystallinity to show a broadX-ray diffraction peak, they can express a heat-ray-shielding effectprovided that the basic binding inside the fine particles is composed ofa bond between each metal and boron.

The lanthanum hexaboride is powder colored to gray black, brown black,green black, or the like, but in the state that it is sufficientlyreduced in particle size, compared to the visible light wavelength, anddispersed in a heat-ray-shielding transparent resin base material, theheat-ray-shielding transparent resin base material can be provided withvisible light transmissivity. However, the infrared light-shieldingability can be maintained at a sufficiently high level. The reasonthereof has not been clarified in detail yet, but it is believed thatsince the amount of free electrons in the fine particles is large andthe absorption energy of an indirect transition between bands by freeelectrons in the inside and on the surfaces of the fine particles is inthe vicinity of from visible to near-infrared, the heat rays in thiswavelength region are selectively reflected or absorbed.

The heat-ray-shielding ability per unit weight of lanthanum hexaborideis very high, and therefore the effect can be exhibited in an amount ofone-fortieth or less compared to those of ITO and ATO. Therefore, sincethe amount of the whole fine particles to be used can be largelyreduced, problems in physical properties of the transparent resinserving as the base material, in particular, in strength, such asdecreases in impact resistant strength and toughness, which are causedby blending a large amount of heat-ray-shielding particles to theheat-ray-shielding transparent resin base material, do not occur.

Since the lanthanum hexaboride exhibits absorption in the visible lightregion by increasing the amount used, the absorption in the visiblelight region can be freely controlled by controlling the addition amountof the lanthanum hexaboride, which can be applied to, for example,adjustment of brightness or protection of privacy.

Furthermore, instead of lanthanum hexaboride, other hexaborides can bealso used, and typical examples thereof include cerium hexaboride(CeB₆), praseodymium hexaboride (PrB₆), neodymium hexaboride (NdB₆),gadolinium hexaboride (GdB₆), terbium hexaboride (TbB₆), dysprosiumhexaboride (DyB₆), holmium hexaboride (HoB₆), yttrium hexaboride (YB₆),samarium hexaboride (SmB₆), europium hexaboride (EuB₆), erbiumhexaboride (ErB₆), thulium hexaboride (TmB₆), ytterbium hexaboride(YbB₆), lutetium hexaboride (LuB₆), lanthanum cerium hexaboride ((La,Ce)B₆), strontium hexaboride (SrB₆), and calcium hexaboride (CaB₆).

b) Titanium Nitride

It is preferable that the surface of TiN used in the present inventionbe not oxidized, but usually the surface is slightly oxidized in manycases, and it is inevitable that the surface is oxidized to some extentin a process of dispersing the fine particles. However, even in such acase, the heat-ray-shielding effect is still effectively expressed. Inaddition, the nitride fine particles can obtain a higherheat-ray-shielding effect with the increasing degree of crystallinity,but even if the fine particles have low crystallinity to show a broadX-ray diffraction peak, they can express a heat-ray-shielding effectprovided that the basic binding inside the fine particles is composed ofa bond between titanium and nitrogen.

The TiN is powder colored to brown black, blue black, or the like, butin the state that it is sufficiently reduced in particle size, comparedto the visible light wavelength, and dispersed in a polycarbonate resin,a film can be provided with visible light transmissivity. However, theinfrared light-shielding ability can be maintained at a sufficientlyhigh level. The reason thereof has not been clarified in detail yet, butit is believed that since the amount of free electrons in the fineparticles is large and the absorption energy of an indirect transitionbetween bands by free electrons in the inside and on the surfaces of thefine particles is in the vicinity of visible to near-infrared, the heatrays in this wavelength region are selectively reflected or absorbed.

Furthermore, instead of TiN, other nitrides can be also used, andtypical examples thereof include fine particles of zirconium nitride(ZrN), hafnium nitride (HfN), vanadium nitride (VN), niobium nitride(NbN), and tantalum nitride (TaN).

c) Tungsten Oxide

The tungsten oxide used in the present invention is preferably acompound defined by a general formula: WO₂ or a general formula: W₁₈^(O) ₄₉. Since the tungsten oxide highly absorbs, in particular, lightin the vicinity of 1000 nm, in many cases, the transmission color toneis a blue-ish color.

2) At least one type of fine particles selected from the groupconsisting of antimony-doped tin oxide, tin-doped indium oxide, and acomposite tungsten oxide defined by a general formula: M_(Y)WO_(Z)(0.001≦Y≦1.0, and 2.2≦Z≦3.0)

The fine particles have optical characteristics of selectively absorbingmiddle-infrared of 1000 nm or more. However, the fine particles are lowin ability of absorbing infrared light with respect to an additionamount per unit area. Therefore, a large amount of the fine particles isnecessary for effectively imparting heat-ray-shielding characteristicsto a base material, and there have been problems of a decrease in themechanical characteristics of the base material itself and an increasein material cost.

a) Antimony-Doped Tin Oxide and Tin-Doped Indium Oxide

The antimony-doped tin oxide and the tin-doped indium oxide used in thepresent invention are preferably surface-treated, for suppressing thephotocatalytic activities specific to the metal oxides, with at leastone surface treating agent selected from the group consisting of asilane coupling agent, a titanium coupling agent, an aluminum couplingagent, and a zirconium coupling agent each having an alkoxyl group andan organic functional group. These surface treating agents to be usedhave affinity to the surfaces of antimony-doped tin oxide fine particlesand have an alkoxyl group for forming a bond and an organic functionalgroup having affinity to a transparent thermoplastic resin. Examples ofthe alkoxyl group include a methoxy group, an ethoxy group, and anisopropoxyl group, but any alkoxyl group that can be hydrolyzed to forma bond with the surface of the antimony-doped tin oxide can be usedwithout particular limitation. Examples of the organic functional groupinclude an alkyl group, a vinyl group, a γ-(2-aminoethyl)aminopropylgroup, a γ-glycidoxypropyl group, a γ-anilinopropyl group, aγ-mercaptopropyl group, and a γ-methacryloxy group, but any organicfunctional group that has affinity to a transparent thermoplastic resincan be used.

b) Composite Tungsten Oxide

The composite tungsten oxide used in the present invention is defined bya general formula, M_(Y)WO_(Z) (0.001≦Y≦1.0, and 2.2≦Z≦3.0), and has ahexagonal crystal structure. Since the composite tungsten oxide highlyabsorbs light in the near-infrared region, in particular, light in thevicinity of 1000 nm, in many cases, the transmission color tone is ablue-ish color tone.

Examples of the composite tungsten oxide fine particle defined by thegeneral formula, M_(Y)WO_(Z) (0.001≦Y≦1.0, and 2.2≦Z≦3.0), and havingthe hexagonal crystal structure include composite tungsten oxide fineparticles of which M element contains at least one selected from thegroup consisting of Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, Sn, Al, andCu.

The addition amount of the addition element M is preferably 0.1 or moreand 0.5 or less and more preferably around 0.33. This is because thatthe value logically calculated from the hexagonal crystal structure is0.33 and that preferable optical characteristics can be obtained in anaddition amount around this value. In addition, the range of the Z ispreferably 2.2≦Z≦3.0. When the value of the Z is 2.45 or higher, theformation of an undesired WO₂ crystal phase in an infraredlight-shielding material can be completely avoided, and chemicalstability of the raw material can be obtained. On the other hand, whenthe value of the Z is 2.999 or less, a sufficient amount of freeelectrons are generated to give a highly efficient infraredlight-shielding material. A value of 2.95 or less is further preferableas an infrared light-shielding material. Furthermore, even in Z≦3.0,free electrons are supplied by the addition of the above-mentionedelement M. From the viewpoint of optical characteristics, it is morepreferably 2.2≦Z≦2.99 and further preferably 2.45≦Z≦2.99.

Here, typical examples of the composite tungsten oxide material includeCs_(0.33)WO₃, Rb_(0.33)WO₃, K_(0.33)WO₃, and Ba_(0.33)WO₃, but as longas the Y and the Z are in the above-mentioned ranges, usefulheat-ray-shielding characteristic can be obtained.

3) Iron Oxide Fine Particle

The iron oxide fine particles can make the value of a*b* [Color tone(D65-10°)] plus and has characteristics of making the color bronze.

Accordingly, the present inventor has mixed the fine particles of theabove-described two groups 1) and 2) so that the materials belonging tothe two groups compensate the respective disadvantages with each other.Thus, the resulting solar-radiation-shielding material has a visiblelight transmittance in the range of 5% or more and 40% or less andsatisfies the following Expression 1 and also has a transmission colorsatisfying the following Expression 2:

solar radiation transmittance/visible light transmittance<1,and  Expression 1

−14<a*<2, and −8<b*<2.  Expression 2

Furthermore, the materials belonging to the above-described three groups1), 2), and 3) compensate the respective disadvantages with one anotherby mixing the fine particles of the three groups. In particular, theaddition of the iron oxide fine particles has characteristics that makethe value of a*b* plus and adjust the color tone to the bronze colorside.

Consequently, the solar-radiation-shielding material can be used to apanorama roof, a back window, and a rear side window of an automobile,which has a relatively low transmittance.

The solar-radiation-shielding material is required to have a visiblelight transmittance of 5% or more and 40% or less. A transmittance lessthan 5% is too low as that of a window, which makes the visibility ofthe outside view significantly low and is therefore undesirable. On theother hand, when the transmittance is higher than 40%, solar-radiationheat including visible light flowing in the inside of a room becomeslarge, and the solar-radiation-shielding material is insufficient forshielding solar radiation, in particular, in midsummer, which makes theair-conditioning cooling load for decreasing the inside temperature highand is therefore undesirable.

In the first aspect of the invention, the transmission color of thesolar-radiation-shielding material is preferably within the ranges of−14<a*<2, and −8<b*<2 in the above-mentioned visible light transmittancerange. When a*≦−14, the green component is too strong, and when 2≦a*,the red component is too strong. Similarly, when b*≦−8, the blueness istoo strong, and when 2≦b*, the yellowness is too strong. Therefore, inthe outside of these ranges, the color deviates from a neutral to darkblue or dark green hue, which is popular among general users, and istherefore undesirable.

In the second aspect of the invention, the transmission color of thesolar-radiation-shielding material is preferably within the range of−2<a*<14, and 2<b*<12. When a*≦−2, the green component is too strong,and when 14≦a*, the red component is too strong. Similarly, when b* 2,the blue component is too strong, and when 12≦b*, the yellow componentis too strong. Therefore, in the outside of these ranges, the colordeviates from a bronze hue, which is popular among general users, and istherefore undesirable.

The diameter of the fine particles having the heat-ray-shieldingfunction is desirably 300 nm or less. A diameter larger than 300 nmcauses scattering of light in the visible light region to make thesolar-radiation-shielding material cloudy and is therefore undesirable.

Furthermore, the fine particles having the solar-radiation-shieldingfunction are preferably surface-treated with at least one selected fromthe group consisting of a silane compound, a titanium compound, azirconia compound, and an aluminum compound. The weather resistance isincreased by coating the fine particle surface with the above-mentionedmaterial. In addition, since the antimony-doped tin oxide and thetin-doped indium oxide have photocatalytic activities specific to themetal oxides, the surface treatment is preferred from the viewpoint ofsuppressing the activities to prevent degradation of the polycarbonateresin.

The addition amount per 1 m² of the heat-ray-shielding fine particles ofthe present invention desirably satisfies the Expression 5 shown below.In the Expression 5, the factor multiplied to each of theheat-ray-shielding fine particles is determined based on the visiblelight absorbing performance per unit weight of the heat-ray shieldingfine particle. For example, when the visible light transmittance of apolycarbonate sheet having a heat-ray-shielding function is controlledto the same value, it is experimentally confirmed that the necessaryaddition amount of titanium oxide per 1 m² is 1/160 of that of tin-dopedindium oxide.

When the value of [(addition amount of titanium nitride(g/m²)×160)+(addition amount of lanthanum hexaboride(g/m²)×40)+(addition amount of tungsten oxide (g/m²)×40)+(compositetungsten oxide (g/m²)×4)+(antimony-doped tin oxide (g/m²))+(tin-dopedindium oxide (g/m²))] is 5 or less, the visible light-absorbingperformance is insufficient and is improper as a panorama roof, a backwindow, and a rear side window of an automobile for the purpose ofprotecting privacy, and also a sufficient heat-ray-shielding abilitycannot be obtained. Conversely, when the value is 50 or more, theabsorption of visible light is too high so that light cannot be taken infrom the outside, though a sufficient heat-ray-shielding ability can beobtained.

5 (g/m²)<(addition amount of titanium nitride (g/m²)×160)+(additionamount of lanthanum hexaboride (g/m²)×40)+(tungsten oxide(g/m²)×40)+(composite tungsten oxide (g/m²)×4)+(antimony-doped tin oxide(g/m²))+(tin-doped indium oxide (g/m²))<50 (g/m²).  Expression 5

In addition, the total addition amount per 1 m² of the fine particles isdesirably 20 g/m² or less. When the total addition amount per 1 m² ishigher than 20 g/m², the mechanical characteristics (impact resistance,surface hardness, and bending strength) of the polycarbonate resinitself may be deteriorated, though it also depends on the thickness ofthe polycarbonate sheet. Furthermore, the material cost is alsoincreased.

In the optical characteristics of the solar-radiation-shielding materialfor vehicle windows containing the fine particles having aheat-ray-shielding function of the present invention, solar radiationtransmittance/visible light transmittance<1. That is, it is desirablethat the value of the solar radiation transmittance is smaller than thatof the visible light transmittance. In the case of solar radiationtransmittance/visible light transmittance>1, the inside of a vehicle istoo dark for sufficiently reducing the solar energy entering into theinside from the outside. The solar radiation transmittance can bereduced by significantly decreasing the visible light transmittance byadding a large amount of a pigment or a dye to the polycarbonate sheet,but it has been conventionally difficult to satisfy solar radiationtransmittance/visible light transmittance<1.

Furthermore, particle size of the heat-ray-shielding fine particles usedin the present invention is preferred as small as possible, and theaverage particle size thereof is 300 nm or less, more preferably 100 nmor less, considering the infrared absorption performance and thetransparency of the resin used. Here, the average particle size isdetermined by observing the powder of heat-ray shielding fine particleswith a transmission electron microscope and calculating the averagevalue of particle sizes of the powder.

The solar-radiation-shielding material can further contain, in additionto the fine particles having a heat-ray-shielding function of thepresent invention, at least one selected from the group consisting ofzinc oxide fine particles, cerium oxide fine particles, and titaniumoxide fine particles as an ultraviolet absorber. Considering thetransparency of the resin used, the average particle size is 300 nm orless and preferably 100 nm or less. Here, the average particle size isdetermined by observing the powder of heat-ray shielding fine particleswith a transmission electron microscope and calculating the averagevalue of particle sizes of the powder.

In order to suppress the photocatalytic activity of the ultravioletabsorber and increase its dispersibility to a transparent thermoplasticresin, the ultraviolet absorber is preferably surface-treated with atleast one surface treating agent selected from the group consisting of asilane coupling agent, a titanium coupling agent, an aluminum couplingagent, and a zirconium coupling agent. These surface treating agents tobe used have affinity to the surface of the ultraviolet absorber andhave an alkoxyl group for forming a bond and an organic functional grouphaving affinity to a transparent thermoplastic resin. Examples of thealkoxyl group include a methoxy group, an ethoxy group, and anisopropoxyl group, but any alkoxyl group that can be hydrolyzed to forma bond with the surface of the inorganic ultraviolet absorber can beused without particular limitation. Examples of the organic functionalgroup include an alkyl group, a vinyl group, aγ-(2-aminoethyl)aminopropyl group, a γ-glycidoxypropyl group, aγ-anilinopropyl group, a γ-mercaptopropyl group, and a γ-methacryloxygroup, but examples are not particularly limited thereto, and anyorganic functional group, that has affinity to a transparentthermoplastic resin can be used.

In addition, in order to increase the dispersibility to the inorganicultraviolet absorber in the thermoplastic resin, an organic polymerdispersant can be simultaneously used with the above-mentioned couplingagent.

2. Structure of Solar-Radiation-Shielding Material for Vehicle Windows

As one configuration of the structure of the solar-radiation-shieldingmaterial for vehicle windows according to the present invention, thesolar-radiation-shielding material for vehicle windows of the first orthe second aspect of the invention includes the fine particles havingthe heat-ray-shielding function contained in a polycarbonate resinmolded product.

The polycarbonate sheet containing the fine particles having theheat-ray-shielding function may have at least one surface provided withan abrasion-resistant hard coat layer. For example, anabrasion-resistant hard coat layer of silicate-based, acrylic-based, orthe like can be formed on the sheet. The abrasion resistance of themolded product can be increased by forming the hard coat layer, and thepolycarbonate sheet containing the fine particles having theheat-ray-shielding function can be used in a panorama roof, a backwindow, and a rear side window of an automobile.

The polycarbonate resin used in the present invention is preferably anaromatic polycarbonate. Examples of the aromatic polycarbonate includepolymers obtained by a known method, such as interfacial polymerization,melt polymerization, or solid phase polymerization, from at least onedivalent phenol-based compound represented by2,2-bis(4-hydroxyphenyl)propane and2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane and a carbonate precursorrepresented by phosgene, diphenyl carbonate, and so on.

Then, any method that can uniformly disperse fine particles in a resincan be arbitrarily selected as the method for dispersing theheat-ray-shielding fine particles in the polycarbonate resin. Forexample, a heat-ray-shielding fine particle dispersion is prepared bydispersing the fine particles in an arbitrary solvent by a method suchas bead milling, ball milling, sand milling, or ultrasonic dispersion. Amixture in which the fine particles are uniformly dispersed in thepolycarbonate resin can be prepared by using a method for uniformlymelt-mixing the dispersion, a powder or pellet of the polycarbonateresin, and, according to need, other additives, while removing thesolvent, using a mixture such as a ribbon blender, a tumbler, a nautamixer, a henschel mixer, a super mixer, or a planetary mixer and akneader such as a banbury mixer, a kneader, a roll, a kneader-ruder, auniaxial extruder, or a biaxial extruder. Alternatively, a mixture inwhich the fine particles are uniformly dispersed in the polycarbonateresin can be prepared by removing the solvent of the heat-ray-shieldingfine particle dispersion by a known method and melt-mixing the resultingpowder, a powder or pellet of the polycarbonate resin, and, according toneed, other additives. Furthermore, a method in which a powder ofheat-ray-shielding fine particles not being dispersion-treated and aheat resistant dispersant are directly added to the polycarbonate resin,and they are uniformly melt-mixed, can be employed. The method is notlimited these methods as long as the heat-ray-shielding fine particlesare uniformly dispersed in the polycarbonate resin.

Examples of the method for forming the polycarbonate sheet containingthe fine particles having the heat-ray-shielding function includearbitrary methods such as injection molding, extrusion molding,compression molding, and rotational molding. In particular, a method forobtaining a molded product by injection molding is suitably employed.The injection molded product can be suitably used in a panorama roof, aback window, and a rear side window of an automobile.

The polycarbonate sheet containing the fine particles having theheat-ray-shielding fine particles can be used by itself in a panoramaroof, a back window, and a rear side window of an automobile and alsocan be used in a constructional material as a heat-ray-shieldingtransparent laminate by being united to another transparent moldedproduct such as inorganic glass, resin glass, or a resin film by anarbitrary method. For example, a transparent laminate having aheat-ray-shielding function and a heat-ray-shielding ability having ascattering-preventing function can be obtained by laminating and unitingthe polycarbonate sheet containing the fine particles having theheat-ray-shielding function, which has been formed into a sheet shape inadvance, to inorganic glass by a heat lamination method.

The transparent laminate having a heat-ray-shielding ability can be alsoobtained by forming the polycarbonate sheet containing the fineparticles having the heat-ray-shielding function and, at the same time,laminating and uniting the sheet to another transparent molded productby a heat lamination method, a coextrusion method, a press moldingmethod, an injection molding method, or the like. The transparentlaminate having the heat-ray-shielding ability can be used as a furtheruseful material for automobile windows by effectively showing advantagesof the respective molded products and, at the same time, compensatingthe respective disadvantages with each other.

Furthermore, the polycarbonate sheet containing the fine particleshaving the heat-ray-shielding function according to the presentinvention can contain usual additives. For example, in addition to a dyeor a pigment that is usually used for coloring a thermoplastic resin forproviding an arbitrary color tone according to need, such as anazo-based dye, a cyanine-based dye, a quinoline-based, a perylene-baseddye, and carbon black, a stabilizer such as a hindered phenol-based orphosphorous-based stabilizer, a mold release agent, an ultravioletabsorber such as a hydroxybenzophenone-based, salicylic acid-based,HALS-based, triazole-based, or triazine-based ultraviolet absorber, acoupling agent, a surfactant, an antistatic agent, and so on can be usedas additives in amounts effectively exhibiting the functions.

Furthermore, as one configuration of the structure of thesolar-radiation-shielding material for vehicle windows according to thepresent invention, it is also preferable that the fine particles havingthe heat-ray-shielding function of the first or the second aspect of theinvention be contained in one selected from the group consisting of apolyvinyl butyral resin, a polyvinyl acetate resin, and a polyvinylalcohol resin and be used as an intermediate film.

It is provided a solar-radiation-shielding material for vehicle windowshaving a laminated structure interposing the above-describedsolar-radiation-shielding material for vehicle windows as anintermediate film between two laminated plates, wherein the laminatedplates are at least one type selected from the group consisting of aninorganic glass plate, a polycarbonate resin molded product, and apolyethylene terephthalate resin molded product.

The solar-radiation-shielding material for vehicle windows can beproduced so that at least one of the two laminated plates is thesolar-radiation-shielding material for vehicle windows in which the fineparticles having the heat-ray-shielding function are contained in thepolycarbonate resin molded product.

The above-described solar-radiation-shielding material for vehiclewindows preferably has a shape with a thickness of 2.5 to 30 mm and amaximum projected area of 400 to 60000 cm².

The maximum size that can be produced by the current injection moldingtechnology is 60000 cm², and therefore a solar-radiation-shieldingmaterial having a size larger than the above is difficult to beproduced. However, it may be possible to produce asolar-radiation-shielding material with a larger size by innovation inmanufacturing apparatuses and injection molding methods in future.Furthermore, a size of 400 cm² or less is too small to be applied tovehicle windows and is therefore inadequate. Similarly, the maximumthickness that can be produced by the current injection moldingtechnology is 30 mm, and therefore a thickness larger than the above isdifficult to be produced. Furthermore, when the thickness is less than2.5 mm, there is a possibility that sufficient rigidity of a vehicleitself is not obtained when the material is mounted on the vehicle.

The solar-radiation-shielding material for vehicle windows of thepresent invention having the above-described many configurations can beapplied to vehicle windows, in particular, a sunroof, a panorama roof, aback window, a rear side window, and a front window of an automobile, asunroof of heavy equipment, and so on, which have required a design thatgives priority to how economically it shields heat of solar rays, ratherthan the brightness.

EXAMPLES

Examples of the present invention will be specifically described withcomparative examples below. However, the present invention is notlimited to the following examples. Furthermore, note that, in eachexample, the dispersion particle size of each type of particle wasmeasured with ELS-8000, manufactured by Otsuka Electronics Co., Ltd.,employing a dynamic light scattering method as the principle.

The visible light transmittance and the solar radiation transmittance ofa solar-radiation-shielding material for vehicle windows were measuredwith a spectrophotometer U-4000 manufactured by Hitachi, Ltd.

Example 1

Ten percents by weight of TiN fine particles, 10% by weight of adispersant, and 80% by weight of toluene were weighed in a paint shakercontaining ZrO₂ beads with a diameter of 0.3 mm and were subjected topulverization and dispersion treatment for 6 hours to prepare a TiN fineparticle dispersion (solution A). Here, the dispersed particle size ofthe oxidized TiN fine particles in the TiN fine particle dispersion(solution A) was measured to be 80 nm.

Furthermore, a dispersant was added to the solution A so that the weightratio of the dispersant and the TiN fine particles was dispersant/TiNfine particles=3. The toluene was removed using a spray dryer to obtainTiN fine particle dispersion powder (hereinafter abbreviated to powderA).

Then, the resulting powder A was added to a polycarbonate resin pelletbeing a thermoplastic resin so that the TiN concentration was 2.0% byweight, followed by uniformly mixing with a blender. The mixture wasmelt-kneaded with a biaxial extruder, and the extruded strand was cutinto a pellet shape to give a polycarbonate master batch containing theTiN fine particles (hereinafter abbreviated to master batch A).

Ten percents by weight of ATO fine particles, 10% by weight of adispersant, and 80% by weight of toluene were weighed in a paint shakercontaining ZrO₂ beads with a diameter of 0.3 mm and were subjected topulverization and dispersion treatment for 6 hours to prepare an ATOfine particle dispersion (solution B). Here, the dispersed particle sizeof the oxidized ATO fine particles in the ATO fine particle dispersion(solution B) was measured to be 63 nm.

Furthermore, a dispersant was added to the solution B so that the weightratio of the dispersant and the ATO fine particles was dispersant/ATOfine particles=3. The toluene was removed using a spray dryer to obtainATO fine particle dispersion powder (hereinafter abbreviated to powderB).

Then, the resulting powder B was added to a polycarbonate resin pelletbeing a thermoplastic resin so that the ATO concentration was 2.0% byweight, followed by uniformly mixing with a blender. The mixture wasmelt-kneaded with a biaxial extruder, and the extruded strand was cutinto a pellet shape to give a polycarbonate master batch containing theATO fine particles (hereinafter abbreviated to master batch B).

Then, the master batch A and the master batch B were diluted with apolycarbonate resin pellet, followed by uniformly mixing with a tumbler.Then, the mixture was extrusion-molded in a thickness of 2.0 mm withT-dies. The addition amounts of the TiN and the ATO were adjusted to0.06 g/m² and 9.6 g/m², respectively, to give asolar-radiation-shielding material 1 according to Example 1 in which theTiN fine particles and the ATO fine particles were uniformly dispersedin the entire resin. Here, the dispersed particle size of the fineparticles of the solar-radiation-shielding material was 75 nm.

As shown in Table 1, the solar radiation transmittance (ST) was 19.1%when the visible light transmittance (VLT) was 31.7%.

Example 2

A solar-radiation-shielding material 2 according to Example 2 wasprepared by the same process as in Example 1 except that the additionamounts of TiN and ATO were adjusted to 0.09 g/m² and 14.4 g/m²,respectively. Here, the dispersed particle size of the fine particles ofthe solar-radiation-shielding material was 78 nm.

As shown in Table 1, the solar radiation transmittance was 15.9% whenthe visible light transmittance was 22.1%.

Example 3

A solar-radiation-shielding material 3 according to Example 3 wasprepared by the same process as in Example 1 except that the additionamounts of TiN and ATO were adjusted to 0.11 g/m² and 1.92 g/m²,respectively. Here, the dispersed particle size of the fine particles ofthe solar-radiation-shielding material was 73 nm.

As shown in Table 1, the solar radiation transmittance was 25.2% whenthe visible light transmittance was 31.9%.

Example 4

Ten percents by weight of ZnO fine particles, 10% by weight of adispersant, and 80% by weight of toluene were weighed in a paint shakercontaining ZrO₂ beads with a diameter of 0.3 mm and were subjected topulverization and dispersion treatment for 3 hours to prepare a ZnO fineparticle dispersion. Furthermore, a dispersant was added to the ZnO fineparticle dispersion so that the weight ratio of the dispersant and theZnO fine particles was dispersant/ZnO fine particles=3. The toluene wasremoved using a spray dryer to obtain ZnO fine particle dispersionpowder.

Then, the resulting ZnO fine particle dispersion powder was added to apolycarbonate resin pellet being a thermoplastic resin so that theconcentration of the ZnO fine particle dispersion powder was 2.0% byweight, followed by uniformly mixing with a blender. The mixture wasmelt-kneaded with a biaxial extruder, and the extruded strand was cutinto a pellet shape to give a polycarbonate master batch containing theZnO fine particles.

Then, a solar-radiation-shielding material 4 according to Example 4 wasprepared by the same process as in Example 3 except that 10% by weightof the polycarbonate master batch containing the ZnO fine particles wereadded. Here, the dispersed particle size of the fine particles of thesolar-radiation-shielding material was 70 nm.

As shown in Table 1, the solar radiation transmittance was 24.2% whenthe visible light transmittance was 30.0%.

Example 5

Ten percents by weight of WO₂ fine particles, 10% by weight of adispersant, and 80% by weight of toluene were weighed in a paint shakercontaining ZrO₂ beads with a diameter of 0.3 mm and were subjected topulverization and dispersion treatment for 6 hours to prepare a WO₂ fineparticle dispersion (solution C). Here, the dispersed particle size ofthe WO₂ fine particles in the WO₂ fine particle dispersion (solution C)was measured to be 55 nm.

Furthermore, a dispersant was added to the solution C so that the weightratio of the dispersant and the WO₂ fine particles was dispersant/WO₂fine particles=3. The toluene was removed using a spray dryer to obtainWO₂ fine particle dispersion powder (hereinafter abbreviated to powderC).

Then, the resulting powder C was added to a polycarbonate resin pelletbeing a thermoplastic resin so that the WO₂ concentration was 2.0% byweight, followed by uniformly mixing with a blender. The mixture wasmelt-kneaded with a biaxial extruder, and the extruded strand was cutinto a pellet shape to give a polycarbonate master batch containing theWO₂ fine particles (hereinafter abbreviated to master batch C).

Then, the master batch B and the master batch C were diluted with apolycarbonate resin pellet, followed by uniformly mixing with a tumbler.Then, the mixture was extrusion-molded in a thickness of 2.0 mm withT-dies. The addition amounts of the WO₂ and the ATO were adjusted to0.44 g/m² and 1.93 g/m², respectively, to give asolar-radiation-shielding material 5 according to Example 5 in which theWO₂ fine particles and the ATO were uniformly dispersed in the entireresin. Here, the dispersed particle size of the fine particles of thesolar-radiation-shielding material was 80 nm.

As shown in Table 1, the solar radiation transmittance was 28.7% whenthe visible light transmittance was 30.5%.

Example 6

Ten percents by weight of ITO fine particles, 10% by weight of adispersant, and 80% by weight of toluene were weighed in a paint shakercontaining ZrO₂ beads with a diameter of 0.3 mm and were subjected topulverization and dispersion treatment for 6 hours to prepare an ITOfine particle dispersion (solution D). Here, the dispersed particle sizeof the ITO fine particles in the ITO fine particle dispersion (solutionD) was measured to be 75 nm.

Furthermore, a dispersant was added to the solution D so that the weightratio of the dispersant and the ITO fine particles was dispersant/ITOfine particles=3. The toluene was removed using a spray dryer to obtainITO fine particle dispersion powder (hereinafter abbreviated to powderD).

Then, the resulting powder D was added to a polycarbonate resin pelletbeing a thermoplastic resin so that the ITO concentration was 2.0% byweight, followed by uniformly mixing with a blender. The mixture wasmelt-kneaded with a biaxial extruder, and the extruded strand was cutinto a pellet shape to give a polycarbonate master batch containing theITO fine particles (hereinafter abbreviated to master batch D).

Then, the master batch C and the master batch D were diluted with apolycarbonate resin pellet, followed by uniformly mixing with a tumbler.Then, the mixture was extrusion-molded in a thickness of 2.0 mm withT-dies. The addition amounts of the WO₂ and the ITO were adjusted to0.44 g/m² and 1.95 g/m², respectively, to give asolar-radiation-shielding material 6 according to Example 6 in which theWO₂ fine particles and the ITO were uniformly dispersed in the entireresin. Here, the dispersed particle size of the fine particles of thesolar-radiation-shielding material was 77 nm.

As shown in Table 1, the solar radiation transmittance was 23.1% whenthe visible light transmittance was 30.9%.

Example 7

Ten percents by weight of LaB₆ fine particles, 10% by weight of adispersant, and 80% by weight of toluene were weighed in a paint shakercontaining ZrO₂ beads with a diameter of 0.3 mm and were subjected topulverization and dispersion treatment for 6 hours to prepare a LaB₆fine particle dispersion (solution E). Here, the dispersed particle sizeof the LaB₆ fine particles in the LaB₆ fine particle dispersion(solution E) was measured to be 68 nm.

Furthermore, a dispersant was added to the solution E so that the weightratio of the dispersant and the LaB₆ fine particles was dispersant/LaB₆fine particles=3. The toluene was removed using a spray dryer to obtainITO fine particle dispersion powder (hereinafter abbreviated to powderE).

Then, the resulting powder E was added to a polycarbonate resin pelletbeing a thermoplastic resin so that the LaB₆ concentration was 2.0% byweight, followed by uniformly mixing with a blender. The mixture wasmelt-kneaded with a biaxial extruder, and the extruded strand was cutinto a pellet shape to give a polycarbonate master batch containing theLaB₆ fine particles (hereinafter abbreviated to master batch E).

Then, the master batch A, the master batch B, and the master batch Ewere diluted with a polycarbonate resin pellet, followed by uniformlymixing with a tumbler. Then, the mixture was extrusion-molded in athickness of 2.0 mm with T-dies. The addition amounts of the LaB₆, theTiN, and the ATO were adjusted to 0.06 g/m², 0.06 g/m², and 1.94 g/m²,respectively, to give a solar-radiation-shielding material 7 accordingto Example 7 in which the LaB₆ fine particles, the TiN fine particles,and the ATO fine particles were uniformly dispersed in the entire resin.Here, the dispersed particle size of the fine particles of thesolar-radiation-shielding material was 85 nm.

As shown in Table 1, the solar radiation transmittance was 27.4% whenthe visible light transmittance was 37.8%.

Example 8

Ten percents by weight of W₁₈O₄₉ fine particles, 10% by weight of adispersant, and 80% by weight of toluene were weighed in a paint shakercontaining ZrO₂ beads with a diameter of 0.3 mm and were subjected topulverization and dispersion treatment for 6 hours to prepare a W₁₈O₄₉fine particle dispersion (solution F). Here, the dispersed particle sizeof the W₁₈O₄₉ fine particles in the W₁₈O₄₉ fine particle dispersion(solution F) was measured to be 69 nm.

Furthermore, a dispersant was added to the solution F so that the weightratio of the dispersant and the W₁₈O₄₉ fine particles wasdispersant/W₁₈O₄₉ fine particles=3. The toluene was removed using aspray dryer to obtain W₁₈O₄₉ fine particle dispersion powder(hereinafter abbreviated to powder F).

Then, the resulting powder F was added to a polycarbonate resin pelletbeing a thermoplastic resin so that the W₁₈ ^(O) ₄₉ concentration was2.0% by weight, followed by uniformly mixing with a blender. The mixturewas melt-kneaded with a biaxial extruder, and the extruded strand wascut into a pellet shape to give a polycarbonate master batch containingthe W₁₈O₄₉ fine particles (hereinafter abbreviated to master batch F).

Then, the master batch B and the master batch F were diluted with apolycarbonate resin pellet, followed by uniformly mixing with a tumbler.Then, the mixture was extrusion-molded in a thickness of 2.0 mm withT-dies. The addition amounts of the W₁₈O₄₉ and the ATO were adjusted to0.43 g/m² and 2.01 g/m², respectively, to give asolar-radiation-shielding material 8 according to Example 8 in which theW₁₈O₄₉ fine particles and the ATO were uniformly dispersed in the entireresin. Here, the dispersed particle size of the fine particles of thesolar-radiation-shielding material was 61 nm.

As shown in Table 1, the solar radiation transmittance was 28.1% whenthe visible light transmittance was 31.8%.

Example 9

Ten percents by weight of Cs_(0.33)WO₃ fine particles, 10% by weight ofa dispersant, and 80% by weight of toluene were weighed in a paintshaker containing ZrO₂ beads with a diameter of 0.3 mm and weresubjected to pulverization and dispersion treatment for 6 hours toprepare a Cs_(0.33)WO₃ fine particle dispersion (solution G). Here, thedispersed particle size of the Cs_(0.33)WO₃ fine particles in theCs_(0.33)WO₃ fine particle dispersion (solution G) was measured to be 77nm.

Furthermore, a dispersant was added to the solution G so that the weightratio of the dispersant and the Cs_(0.33)WO₃ fine particles wasdispersant/Cs_(0.33)WO₃ fine particles=3. The toluene was removed usinga spray dryer to obtain Cs_(0.33)WO₃ fine particle dispersion powder(hereinafter abbreviated to powder G).

Then, the resulting powder G was added to a polycarbonate resin pelletbeing a thermoplastic resin so that the Cs_(0.33)WO₃ concentration was2.0% by weight, followed by uniformly mixing with a blender. The mixturewas melt-kneaded with a biaxial extruder, and the extruded strand wascut into a pellet shape to give a polycarbonate master batch containingthe Cs_(0.33)WO₃ fine particles (hereinafter abbreviated to master batchG).

Then, the master batch A and the master batch G were diluted with apolycarbonate resin pellet, followed by uniformly mixing with a tumbler.Then, the mixture was extrusion-molded in a thickness of 2.0 mm withT-dies. The addition amounts of the TiN and the Cs_(0.33)WO₃ wereadjusted to 0.06 g/m² and 2.4 g/m², respectively, to give asolar-radiation-shielding material 9 according to Example 9 in which theTiN fine particles and the Cs_(0.33)WO₃ were uniformly dispersed in theentire resin. Here, the dispersed particle size of the fine particles ofthe solar-radiation-shielding material was 79 nm.

As shown in Table 1, the solar radiation transmittance was 15.7% whenthe visible light transmittance was 31.7%.

Example 10

A solar-radiation-shielding material 10 according to Example 9 wasprepared by the same process as in Example 10 except that the additionamounts of TiN and Cs_(0.33)WO₃ were adjusted to 0.15 g/m² and 6.0 g/m²,respectively. Here, the dispersed particle size of the fine particles ofthe solar-radiation-shielding material was 66 nm.

As shown in Table 1, the solar radiation transmittance was 7.1% when thevisible light transmittance was 10.1%.

Example 11

Ten percents by weight of Fe₂O₃ fine particles, 10% by weight of adispersant, and 80% by weight of toluene were weighed in a paint shakercontaining ZrO₂ beads with a diameter of 0.3 mm and were subjected topulverization and dispersion treatment for 6 hours to prepare a Fe₂O₃fine particle dispersion (solution H). Here, the dispersed particle sizeof the Fe₂O₃ fine particles in the Fe₂O₃ fine particle dispersion(solution H) was measured to be 50 nm.

Furthermore, a dispersant was added to the solution H so that the weightratio of the dispersant and the Fe₂O₃ fine particles wasdispersant/Fe₂O₃ fine particles=3. The toluene was removed using a spraydryer to obtain Fe₂O₃ fine particle dispersion powder (hereinafterabbreviated to powder H).

Then, the resulting powder H was added to a polycarbonate resin pelletbeing a thermoplastic resin so that the Fe₂O₃ concentration was 2.0% byweight, followed by uniformly mixing with a blender. The mixture wasmelt-kneaded with a biaxial extruder, and the extruded strand was cutinto a pellet shape to give a polycarbonate master batch containing theFe₂O₃ fine particles (hereinafter abbreviated to master batch H).

Then, the master batch A, the master batch G, and the master batch Hwere diluted with a polycarbonate resin pellet, followed by uniformlymixing with a tumbler. Then, the mixture was extrusion-molded in athickness of 2.0 mm with T-dies. The addition amounts of the TiN, theCs_(0.33)WO₃, and the Fe₂O₃ were adjusted to 0.06 g/m², 2.4 g/m², and0.6 g/m², respectively, to give a solar-radiation-shielding material 11according to Example 11 in which the TiN fine particles, theCs_(0.33)WO₃, and the Fe₂O₃ fine particles were uniformly dispersed inthe entire resin. Here, the dispersed particle size of the Fe₂O₃ fineparticles of the solar-radiation-shielding material was 81 nm.

As shown in Table 1, the solar radiation transmittance was 25.0% whenthe visible light transmittance was 26.6%.

Example 12

Three percents by weight of TiN fine particles and 97% by weight ofisopropyl alcohol were weighed in a paint shaker containing ZrO₂ beadswith a diameter of 0.3 mm and were subjected to pulverization anddispersion treatment for 6 hours. Then, methyltrimethoxysilane was addedthereto, followed by mixing by stirring with a mechanical stirrer for 1hour. Then, the isopropyl alcohol was removed using a spray dryer togive TiN fine particles surface-treated with a silane compound.

Three percents by weight of ATO fine particles and 97% by weight ofisopropyl alcohol were weighed in a paint shaker containing ZrO₂ beadswith a diameter of 0.3 mm and were subjected to pulverization anddispersion treatment for 6 hours. Then, methyltrimethoxysilane was addedthereto, followed by mixing by stirring with a mechanical stirrer for 1hour. Then, the toluene was removed using a spray dryer to give ATO fineparticles surface-treated with a silane compound.

A solar-radiation-shielding material 12 according to Example 12 wasprepared as in Example 1 except that the TiN fine particlessurface-treated with a silane compound and the ATO fine particlessurface-treated with a silane compound were used.

The dispersed particle size of the fine particles of thesolar-radiation-shielding material was 83 nm.

As shown in Table 1, the solar radiation transmittance was 19.2% whenthe visible light transmittance was 31.5%.

Example 13

An abrasion-resistant hard coat solution was prepared by mixing 50% byweight of Aronix M-400 manufactured by Toa Gosei, 5% by weight ofIrgacure 651 manufactured by Ciba Specialty, and 45% by weight oftoluene. The abrasion-resistant hard coat solution was applied to thesurface of the solar-radiation-shielding material 1 produced by the sameprocess as in Example 1 using a bar coater #20, followed by drying at70° C. for 1 minute and then irradiation with UV light of 140 mW/cm²using a high-pressure mercury lamp. Thus, an abrasion-resistant hardcoat layer was formed to give a solar-radiation-shielding material 13.

As shown Table 1, the solar radiation transmittance was 18.9% when thevisible light transmittance 31.2%.

The pencil hardness was measured to confirm that the pencil hardness ofthe solar-radiation-shielding material 13 was increased to 2H by formingthe abrasion-resistant hard coat layer. The pencil hardness of thesolar-radiation-shielding material 1 produced in Example 1 was F.

Thus, the abrasion resistance of a solar-radiation-shielding materialcan be increased by forming an abrasion-resistant hard coat layer on thesurface of the solar-radiation-shielding material, and thesolar-radiation-shielding material can be used to, for example, windowsof vehicles and automobiles.

Example 14

The TiN fine particle dispersion (solution A) and 50% by weight of aplasticizer, triethylene glycol-di-2-ethyl butyrate, were weighed,followed by removal of toluene with an agitating vacuum dryer to producea TiN plasticizer dispersion (plasticizer solution A).

Similarly, the ATO fine particle dispersion (solution B) and 50% byweight of the plasticizer, triethylene glycol-di-2-ethyl butyrate, wereweighed, followed by removal of toluene with an agitating vacuum dryerto produce an ATO plasticizer dispersion (plasticizer solution B).

The plasticizer solution A and the plasticizer solution B were added toa polyvinyl butyral resin, followed by addition of triethyleneglycol-di-2-ethyl butyrate as a plasticizer. The resulting mixture waskneaded with a roll and formed into a sheet-like shape having athickness of 0.5 mm. The addition amounts of the TiN and the ATO wereadjusted to 0.06 g/m² and 9.60 g/m², respectively, to give anintermediate film (intermediate film A) in which the TiN fine particlesand the ATO were uniformly dispersed in the entire resin.

Then, the intermediate film A was interposed between two float glassplates each having a thickness of 2 mm, and they were heated andpressure bonded according to a usual method for producing laminatedglass to obtain a solar-radiation-shielding material 14. The dispersedparticle size of the fine particles of the solar-radiation-shieldingmaterial was 69 nm.

Furthermore, as shown in Table 1, the solar radiation transmittance was19.0% when the visible light transmittance was 30.8%.

Example 15

A solar-radiation-shielding material 15 according to Example 15 wasprepared by the same process as in Example 13 except that the additionamounts of the TiN and the ATO were 0.09 g/m² and 14.4 g/m²,respectively. Furthermore, the dispersed particle size of the fineparticles of the solar-radiation-shielding material was 78 nm.

As shown in Table 1, the solar radiation transmittance was 15.7% whenthe visible light transmittance was 21.1%.

Example 16

A solar-radiation-shielding material 16 according to Example 16 wasprepared by the same process as in Example 1 except that the additionamounts of the TiN and the ATO were 0.11 g/m² and 1.92 g/m²,respectively. Furthermore, the dispersed particle size of the fineparticles of the solar-radiation-shielding material was 73 nm.

As shown in Table 1, the solar radiation transmittance was 25.0% whenthe visible light transmittance was 30.9%.

Example 17

The WO₂ fine particle dispersion (solution C) and 50% by weight of aplasticizer, triethylene glycol-di-2-ethyl butyrate, were weighed,followed by removal of toluene with an agitating vacuum dryer to producea WO₂ plasticizer dispersion (plasticizer solution C).

The plasticizer solution A and the plasticizer solution C were added toa polyvinyl butyral resin, followed by addition of triethyleneglycol-di-2-ethyl butyrate as a plasticizer. The resulting mixture waskneaded with a roll and formed into a sheet-like shape having athickness of 0.5 mm. The addition amounts of the WO₂ and the ATO wereadjusted to 0.44 g/m² and 1.93 g/m², respectively, to give anintermediate film (intermediate film D) in which the WO₂ fine particlesand the ATO were uniformly dispersed in the entire resin.

Then, the intermediate film D was interposed between two float glassplates each having a thickness of 2 mm, and they were heated andpressure bonded according to a usual method for producing laminatedglass to obtain a solar-radiation-shielding material 17. The dispersedparticle size of the fine particles of the solar-radiation-shieldingmaterial was 77 nm.

As shown in Table 1, the solar radiation transmittance was 28.4% whenthe visible light transmittance was 30.5%.

Example 18

The ITO fine particle dispersion (solution D) and 50% by weight of aplasticizer, triethylene glycol-di-2-ethyl butyrate, were weighed,followed by removal of toluene with an agitating vacuum dryer to producean ITO plasticizer dispersion (plasticizer solution D).

The plasticizer solution C and the plasticizer solution D were added toa polyvinyl butyral resin, followed by addition of triethyleneglycol-di-2-ethyl butyrate as a plasticizer. The resulting mixture waskneaded with a roll and formed into a sheet-like shape having athickness of 0.5 mm. The addition amounts of the WO₂ and the ITO wereadjusted to 0.44 g/m² and 1.95 g/m², respectively, to give anintermediate film (intermediate film E) in which the WO₂ fine particlesand the ITO were uniformly dispersed in the entire resin.

Then, the intermediate film E was interposed between two float glassplates each having a thickness of 2 mm, and they were heated andpressure bonded according to a usual method for producing laminatedglass to obtain a solar-radiation-shielding material 18. The dispersedparticle size of the fine particles of the solar-radiation-shieldingmaterial was 81 nm.

As shown in Table 1, the solar radiation transmittance was 22.4% whenthe visible light transmittance was 30.1%.

Example 19

The LaB₆ fine particle dispersion (solution E) and 50% by weight of aplasticizer, triethylene glycol-di-2-ethyl butyrate, were weighed,followed by removal of toluene with an agitating vacuum dryer to producea LaB₆ plasticizer dispersion (plasticizer solution E).

The plasticizer solution A, the plasticizer solution B, and theplasticizer solution E were added to a polyvinyl butyral resin, followedby addition of triethylene glycol-di-2-ethyl butyrate as a plasticizer.The resulting mixture was kneaded with a roll and formed into asheet-like shape having a thickness of 0.5 mm. The addition amounts ofthe LaB₆, the TiN, and the ATO were adjusted to 0.06 g/m², 0.06 g/m²,and 1.94 g/m², respectively, to give an intermediate film (intermediatefilm F) in which the LaB₆ fine particles, the TiN fine particles, andthe ATO were uniformly dispersed in the entire resin.

Then, the intermediate film F was interposed between two float glassplates each having a thickness of 2 mm, and they were heated andpressure bonded according to a usual method for producing laminatedglass to obtain a solar-radiation-shielding material 19. The dispersedparticle size of the fine particles of the solar-radiation-shieldingmaterial was 79 nm.

As shown in Table 1, the solar radiation transmittance was 27.3% whenthe visible light transmittance was 37.5%.

Example 20

The W₁₈O₄₉ fine particle dispersion (solution F) and 50% by weight of aplasticizer, triethylene glycol-di-2-ethyl butyrate, were weighed,followed by removal of toluene with an agitating vacuum dryer to producea W₁₈O₄₉ plasticizer dispersion (plasticizer solution F).

The plasticizer solution B and the plasticizer solution F were added toa polyvinyl butyral resin, followed by addition of triethyleneglycol-di-2-ethyl butyrate as a plasticizer. The resulting mixture waskneaded with a roll and formed into a sheet-like shape having athickness of 0.5 mm. The addition amounts of the W₁₈O₄₉ and the ATO wereadjusted to 0.43 g/m² and 2.01 g/m², respectively, to give anintermediate film (intermediate film G) in which the W₁₈O₄₉ fineparticles and the ATO fine particles were uniformly dispersed in theentire resin.

Then, the intermediate film G was interposed between two float glassplates each having a thickness of 2 mm, and they were heated andpressure bonded according to a usual method for producing laminatedglass to obtain a solar-radiation-shielding material 20. The dispersedparticle size of the fine particles of the solar-radiation-shieldingmaterial was 79 nm.

As shown in Table 1, the solar radiation transmittance was 29.1% whenthe visible light transmittance was 31.4%.

Example 21

The Cs_(0.33)WO₃ fine particle dispersion (solution G) and 50% by weightof a plasticizer, triethylene glycol-di-2-ethyl butyrate, were weighed,followed by removal of toluene with an agitating vacuum dryer to producea Cs_(0.33)WO₃ plasticizer dispersion (plasticizer solution G).

The plasticizer solution A and the plasticizer solution G were added toa polyvinyl butyral resin, followed by addition of triethyleneglycol-di-2-ethyl butyrate as a plasticizer. The resulting mixture waskneaded with a roll and formed into a sheet-like shape having athickness of 0.5 mm. The addition amounts of the TiN and theCs_(0.33)WO₃ were adjusted to 0.06 g/m² and 2.4 g/m², respectively, togive an intermediate film (intermediate film H) in which the TiN fineparticles and the Cs_(0.33)WO₃ fine particles were uniformly dispersedin the entire resin.

Then, the intermediate film H was interposed between two float glassplates each having a thickness of 2 mm, and they were heated andpressure bonded according to a usual method for producing laminatedglass to obtain a solar-radiation-shielding material 21. The dispersedparticle size of the fine particles of the solar-radiation-shieldingmaterial was 75 nm.

As shown in Table 1, the solar radiation transmittance was 15.6% whenthe visible light transmittance was 31.3%.

Example 22

A solar-radiation-shielding material 22 according to Example 22 wasprepared by the same process as in Example 20 except that the additionamounts of the TiN and the Cs_(0.33)WO₃ were 0.15 g/m² and 6.00 g/m²,respectively. Furthermore, the dispersed particle size of the fineparticles of the solar-radiation-shielding material was 72 nm.

As shown in Table 1, the solar radiation transmittance was 7.0% when thevisible light transmittance was 10.1%.

Example 23

The Fe₂O₃ fine particle dispersion (solution H) and 50% by weight of aplasticizer, triethylene glycol-di-2-ethyl butyrate, were weighed,followed by removal of toluene with an agitating vacuum dryer to producea Fe₂O₃ plasticizer dispersion (plasticizer solution H).

The plasticizer solution A, the plasticizer solution G, and theplasticizer solution H were added to a polyvinyl butyral resin, followedby addition of triethylene glycol-di-2-ethyl butyrate as a plasticizer.The resulting mixture was kneaded with a roll and formed into asheet-like shape having a thickness of 0.5 mm. The addition amounts ofthe TiN, the Cs_(0.33)WO₃, and the Fe₂O₃ were adjusted to 0.06 g/m², 2.4g/m², and 0.6 g/m², respectively, to give an intermediate film(intermediate film J) in which the TiN fine particles, the Cs_(0.33)WO₃fine particles, and the Fe₂O₃ were uniformly dispersed in the entireresin.

Then, the intermediate film J was interposed between two float glassplates each having a thickness of 2 mm, and they were heated andpressure bonded according to a usual method for producing laminatedglass to obtain a solar-radiation-shielding material 23. The dispersedparticle size of the fine particles of the solar-radiation-shieldingmaterial was 67 nm.

As shown in Table 1, the solar radiation transmittance was 24.8% whenthe visible light transmittance was 26.5%.

Example 24

The intermediate film H was interposed between a float glass platehaving a thickness of 2 mm and the solar-radiation-shielding material 6,and they were heated and pressure bonded according to a usual method forproducing laminated glass to obtain a solar-radiation-shielding material24.

As shown in Table 1, the solar radiation transmittance was 11.6% whenthe visible light transmittance was 17.9%.

Example 25

The intermediate film H was interposed between a float glass platehaving a thickness of 2 mm and a polyethylene terephthalate film, andthey were heated and pressure bonded according to a usual method forproducing laminated glass to obtain a solar-radiation-shielding material25.

As shown in Table 1, the solar radiation transmittance was 16.2% whenthe visible light transmittance was 31.9%.

Comparative Example 1

The master batch B and a blue-coloring dye (anthraquinone-based blue dye(trade name: Polysynthren Blue RLS, manufactured by Clariant)) werediluted with a polycarbonate resin pellet, followed by uniformly mixingwith a tumbler. Then, the mixture was extrusion-molded in a thickness of2.0 mm with T-dies. The addition amount of the ATO was adjusted to 1.96g/m² to give a solar-radiation-shielding material 26 according toComparative Example 1 in which the ATO fine particles were uniformlydispersed in the entire resin and the blue-based dye was contained.Here, the dispersed particle size of the ATO fine particles of thesolar-radiation-shielding material was 84 nm.

As shown in Table 1, the solar radiation transmittance was 39.6% whenthe visible light transmittance was 31.7%.

The ratio of solar radiation transmittance/visible light transmittancewas 1.25, and the requirement, solar radiation transmittance/visiblelight transmittance<1, could not be satisfied.

The visible light transmittance could be reduced by using the ATO andthe blue-based dye, but the solar radiation transmittance could not besufficiently reduced. Therefore, the effect for suppressing the increasein inside temperature is low, and the use to vehicle windows isimproper.

Comparative Example 2

The master batch A and the master batch D were diluted with apolycarbonate resin pellet, followed by uniformly mixing with a tumbler.Then, the mixture was extrusion-molded in a thickness of 2.0 mm withT-dies. The addition amounts of the TiN and the ITO were adjusted to0.016 g/m² and 2.40 g/m², respectively, to give asolar-radiation-shielding material 27 according to Comparative Example 2in which the TiN fine particles and the ITO fine particles wereuniformly dispersed in the entire resin. Here, the dispersed particlesize of the fine particles of the solar-radiation-shielding material was69 nm.

As shown in Table 1, the solar radiation transmittance was 40.5% whenthe visible light transmittance was 65.2%.

The value of 0.016 g/m² (addition amount of TiN)×160+2.4 g/m² (additionamount of ITO) was 4.96, and the addition amounts of the heat-rayshielding fine particles did not satisfy the following Expression 5shown in context. Thus, the visible light transmittance could not besufficiently reduced, and, therefore, the use to vehicle windows forprotecting privacy is improper.

5 (g/m²)<(addition amount of titanium nitride (g/m²)×160)+(additionamount of lanthanum hexaboride (g/m²)×40)+(tungsten oxide(g/m²)×40)+(composite tungsten oxide (g/m²)×4)+(antimony-doped tin oxide(g/m²))+(tin-doped indium oxide (g/m²))<50 (g/m²).  Expression 5

Comparative Example 3

The master batch A and the master batch B were diluted with apolycarbonate resin pellet, followed by uniformly mixing with a tumbler.Then, the mixture was extrusion-molded in a thickness of 2.0 mm withT-dies. The addition amounts of the TiN and the ATO were adjusted to0.19 g/m² and 19.9 g/m², respectively, to give asolar-radiation-shielding material 28 according to Comparative Example 3in which the TiN fine particles and the ATO fine particles wereuniformly dispersed in the entire resin. Here, the dispersed particlesize of the fine particles of the solar-radiation-shielding material was76 nm.

As shown in Table 1, the solar radiation transmittance was 3.3% when thevisible light transmittance was 3.4%.

The value of 0.19 g/m² (addition amount of TiN)×160+2.4 g/m² (additionamount of ATO) was 50.3, and the addition amounts of the heat-rayshielding fine particles did not satisfy the Expression 5 shown incontext. Thus, the visible light transmittance was too low, and,therefore, the use to vehicle windows is improper.

The total addition amount per 1 m² of the heat-ray-shielding fineparticles was 20.1 g/m², which was higher than the level of 20 g/m² orless shown in context. Thus, the solar-radiation-shielding material hada significantly low surface hardness and was readily damaged by beingscratched with nail, and, therefore, the use to vehicle windows isimproper. In addition, the material cost is also increased.

Comparative Example 4

The master batch C was diluted with a polycarbonate resin pellet,followed by uniformly mixing with a tumbler. Then, the mixture wasextrusion-molded in a thickness of 2.0 mm with T-dies. The additionamount of the WO₂ was adjusted to 0.44 g/m² to give asolar-radiation-shielding material 29 according to Comparative Example 4in which the WO₂ fine particles were uniformly dispersed in the entireresin. Here, the dispersed particle size of the fine particles of thesolar-radiation-shielding material was 76 nm.

As shown in Table 1, the solar radiation transmittance was 45.7% whenthe visible light transmittance was 35.9%.

The ratio of solar radiation transmittance/visible light transmittancewas 1.27, and the requirement, solar radiation transmittance/visiblelight transmittance<1, could not be satisfied. Since WO₂ was used alone,the absorption of infrared of 1000 nm or more was insufficient, and thesolar radiation transmittance could not be sufficiently reduced.Therefore, the effect for suppressing the increase in inside temperatureis low, and the use to vehicle windows is improper.

TABLE 1 Heat-ray-shielding Total Optical material addition amountcharacteristics Color tone amount (g/m²) of fillers VLT ST (D65-10°)LaB₆ TiN WO₂ W₁₈O₄₉ Cs_(0.33)WO₂ ATO ITO Fe₂O₃ 00(g/m²) (%) (%) ST/VLTa* b* Example 1 0.060 9.600 9.66 31.7 19.1 0.60 −4.68 1.37 Example 20.090 14.400 14.49 22.1 15.9 0.72 −6.22 1.43 Example 3 0.110 1.920 2.0331.9 25.2 0.79 −3.56 −5.04 Example 4 0.110 1.920 2.03 30.0 24.2 0.80−3.40 −4.88 Example 5 0.440 1.930 2.37 30.5 28.7 0.94 −2.67 −6.10Example 6 0.440 1.950 2.39 30.9 23.1 0.74 −2.78 −6.20 Example 7 0.0600.060 1.940 2.06 37.8 27.4 0.72 −5.10 1.89 Example 8 0.430 2.010 2.4431.8 28.1 0.88 −2.67 −5.12 Example 9 0.060 2.400 2.46 31.7 15.7 0.49−10.20 −6.30 Example 10 0.150 6.000 6.15 10.1 7.1 0.70 −13.90 −7.90Example 11 0.060 2.400 0.600 3.06 26.6 25.0 0.93 4.35 3.78 Example 120.060 9.600 9.66 31.5 19.2 0.61 −4.72 1.31 Example 13 0.060 9.600 9.6631.2 18.9 0.61 −4.55 1.32 Example 14 0.060 9.600 9.66 30.8 19.0 0.62−5.18 0.87 Example 15 0.090 14.400 14.49 21.1 15.7 0.74 −6.71 0.98Example 16 0.110 1.920 2.03 30.9 25.0 0.81 −4.01 −5.52 Example 17 0.4401.930 2.37 30.5 28.4 0.93 −3.16 −6.57 Example 18 0.440 1.950 2.39 30.122.4 0.74 −3.21 −6.63 Example 19 0.060 0.060 1.940 2.06 37.5 27.3 0.73−5.55 1.89 Example 20 0.430 2.010 2.44 31.4 29.1 0.93 −3.00 −5.12Example 21 0.060 2.400 2.46 31.3 15.6 0.50 −10.88 −6.30 Example 22 0.1506.000 6.15 10.1 7.0 0.70 −13.99 −7.98 Example 23 0.060 2.400 0.600 3.0626.5 24.8 0.93 3.96 3.23 Example 24 0.060 0.120 2.400 1.940 4.52 17.911.6 0.65 −8.45 −2.95 Example 25 0.060 2.400 2.46 31.9 16.2 0.51 −9.98−6.02 Comparative 1.960 1.96 31.7 39.6 1.25 −3.05 −5.21 Example 1Comparative 0.016 2.400 2.42 65.2 40.5 0.62 −1.35 −0.35 Example 2Comparative 0.190 19.900 20.10 3.4 3.3 0.97 −13.82 −7.90 Example 3Comparative 0.440 0.44 35.9 45.7 1.27 −3.80 −8.92 Example 4

1. A solar-radiation-shielding material for vehicle windows, thematerial comprising fine particles having a heat-ray-shielding functionused in a window of a vehicle, wherein the fine particles having theheat-ray-shielding function are a mixture including at least one type offine particles selected from the group consisting of lanthanumhexaboride, titanium nitride, and tungsten oxide and at least one typeof fine particles selected from the group consisting of antimony-dopedtin oxide, tin-doped indium oxide, and a composite tungsten oxidedefined by a general formula: M_(Y)WO_(Z) (0.001≦Y≦1.0, and 2.2≦Z≦3.0);the visible light transmittance of the solar-radiation-shieldingmaterial is in the range of 5% or more and 40% or less; the solarradiation transmittance and the visible light transmittance of thesolar-radiation-shielding material satisfy the following Expression 1;and the transmission color of the solar-radiation-shielding materialsatisfies the following Expression 2:solar radiation transmittance/visible light transmittance<1,and  Expression 1−14<a*<2, and −8<b*<2.  Expression 2
 2. A solar-radiation-shieldingmaterial for vehicle windows, the material comprising fine particleshaving a heat-ray-shielding function used in a window of a vehicle,wherein the fine particles having the heat-ray-shielding function are amixture including at least one type of fine particles selected from thegroup consisting of lanthanum hexaboride, titanium nitride, and tungstenoxide, at least one type of fine particles selected from the groupconsisting of antimony-doped tin oxide, tin-doped indium oxide, and acomposite tungsten oxide defined by a general formula: M_(Y)WO_(Z)(0.001≦Y≦1.0, and 2.2≦Z≦3.0), and iron oxide fine particles; the visiblelight transmittance of the solar-radiation-shielding material is in therange of 5% or more and 40% or less; the solar radiation transmittanceand the visible light transmittance of the solar-radiation-shieldingmaterial satisfy the following Expression 3; and the transmission colorof the solar-radiation-shielding material satisfies the followingExpression 4:solar radiation transmittance/visible light transmittance<1,and  Expression 3−2<a*<14, and 2<b*<12.  Expression 4
 3. The solar-radiation-shieldingmaterial for vehicle windows according to claim 2, wherein the tungstenoxide is WO₂ or W₁₈O₄₉.
 4. The solar-radiation-shielding material forvehicle windows according to claim 2, wherein the element M contained inthe composite tungsten oxide fine particle is at least one selected fromthe group consisting of Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn.5. The solar-radiation-shielding material for vehicle windows accordingto claim 4, wherein the fine particles having the heat-ray-shieldingfunction have a diameter of 300 nm or less.
 6. Thesolar-radiation-shielding material for vehicle windows according toclaim 5, wherein the fine particles having the heat-ray-shieldingfunction are surface-treated with at least one type of compound selectedfrom the group consisting of a silane compound, a titanium compound, anda zirconia compound.
 7. The solar-radiation-shielding material forvehicle windows according to claim 6, the solar-radiation-shieldingmaterial further comprising at least one type of fine particles selectedfrom the group consisting of zinc oxide fine particles, cerium oxidefine particles, and titanium oxide fine particles.
 8. Thesolar-radiation-shielding material for vehicle windows according toclaim 7, wherein the fine particles having the heat-ray-shieldingfunction are contained in a polycarbonate resin molded product.
 9. Thesolar-radiation-shielding material for vehicle windows according toclaim 8, wherein the polycarbonate resin molded product is provided withan abrasion-resistant hard coat layer on at least one surface.
 10. Thesolar-radiation-shielding material for vehicle windows according toclaim 9, the solar-radiation-shielding material further comprisinganother resin molded product being laminated.
 11. Thesolar-radiation-shielding material for vehicle windows according toclaim 7, wherein the fine particles having the heat-ray-shieldingfunction are contained in one type of resin selected from the groupconsisting of a polyvinyl butyral resin, a polyvinyl acetate resin, anda polyvinyl alcohol resin.
 12. A solar-radiation-shielding material forvehicle windows having a laminated structure comprising thesolar-radiation-shielding material according to claim 11 interposed asan intermediate film between two laminated plates, wherein the laminatedplates are at least one selected from the group consisting of aninorganic glass plate, a polycarbonate resin molded product, and apolyethylene terephthalate resin molded product.
 13. Thesolar-radiation-shielding material for vehicle windows according toclaim 12, wherein at least one of the laminated plates is formed fromthe solar-radiation-shielding material according.
 14. Thesolar-radiation-shielding material for vehicle windows according toclaim 13, the material having a shape of a thickness of from 2.5 to 30mm and a maximum projected area of from 400 to 60000 cm².
 15. A windowof a vehicle, the window comprising a solar-radiation-shielding materialfor vehicle windows according to claim 1.